Vibratory feeders have a number of applications such as, for example, the feeding of pulverulent material in various industrial processes. An example of a vibratory feeder of this type is shown in my earlier U.S. Pat. No. 3,089,582. The apparatus in said patent, while operating efficiently to feed material at a uniform rate, operates at a constant speed and hence produces a constant rate of feed. Obviously, it is desirable that in many installations the rate of feed be variable. Such a variable rate of feed was achieved by my subsequent U.S. Pat. No. 3,358,815. In the latter patent, control is effected pneumatically, i.e., air pressure is utilized for the purposes described. While operating effectively, there are disadvantages to a pneumatic control, which disadvantages can be overcome by means of the present invention.